Summary Edexcel iGCSE Chemistry Revision notes on cracking

CRACKING

cracking : breakdown of large alcanes into smaller more useful accane and
alkenes using heat
THERMAL DECOMPOSITION




NNN H
4 M H M HH H I 111
HH
1 -H
H c c C C C C C C H he at c C H C
H c C H c C C
- - -

+
- - - - - -
=
>
- - - - - - - -

-




it isa isi itw i it iti is i ww H
CHiz CH ,o 24Hz
alkane alkene
formula for formula for
Alkames Alkenes saturated unsaturated

In Han + 2 CnHzn
at least one

double bond between

the carbon atoms
saturated hydrocarbons make the maximum number of
bonds and contains single bonds only




ALKENES
carbon display molecular molecular Name
number structure Structure formula



1


Hy ~
H
CH2CH2 etheme
C2Ha
2 /
C
=
H H


H H
-
H

3 H -
-
= c CHzCHCHz C3Hy propene
H

H HH
1 1 1 H
CHzCHeCHCH2 CHz butene
& H -

c -
C -

C = C

it i H

H HH H H

c
11 I

3 H -
c -

c -
c -
c = CH3CHzCHzCHCH2 CsHio pentene

Hi H H